Add commentary, fix broken relative symlink resolution

realpath.sh

@@ -14,37 +14,49 @@ result=""
 while [ -n "$left" ]; do
   case "$left" in
   */*)
+    # Snip one path segment off $left
     seg="${left%%/*}"
     left="${left#*/}"
     ;;
   *)
+    # Last path segment already
     seg="$left"
     left=""
     ;;
   esac
+
   case "$seg" in
   .)
+    # /foo/a -> . will become /foo
     result="${result%/*}"
     continue
     ;;
   ..)
+    # /foo/bar/a -> .. will become /foo
     result="${result%/*/*}"
     continue
     ;;
   esac
+
   result="$result/$seg"
   target="$(readlink "$result")"
+
   case "$target" in
   /*)
-    left="${target}"
+    # Absolute symlink. Resets buildup of $result
+    left="${target}/${left}"
     result=""
     ;;
   '')
+    # Readlink failed, its not a symlink
     ;;
   *)
-    left="${left%/*}/${target}"
+    # Relative symlink: Keep $result, its the symlink base
+    left="${target}/${left}"
     ;;
   esac
+
+  # Make sure $left never starts with a slash
   left="${left#/}"
 done